// Copyright 2011 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_SNAPSHOT_NATIVES_H_
#define V8_SNAPSHOT_NATIVES_H_

#include "include/v8.h"
#include "src/objects.h"
#include "src/vector.h"

namespace v8 {
class StartupData;
} // Forward declaration.

namespace v8 {
namespace internal {

    enum NativeType {
        EXTRAS,
        TEST
    };

    // Extra handling for V8_EXPORT_PRIVATE in combination with USING_V8_SHARED
    // since definition of methods of classes marked as dllimport is not allowed.
    template <NativeType type>
#ifdef USING_V8_SHARED
    class NativesCollection {
#else
    class V8_EXPORT_PRIVATE NativesCollection {
#endif // USING_V8_SHARED

    public:
        // The following methods are implemented in js2c-generated code:

        // Number of built-in scripts.
        static int GetBuiltinsCount();
        static int GetIndex(const char* name);
        static Vector<const char> GetScriptSource(int index);
        static Vector<const char> GetScriptName(int index);
        static Vector<const char> GetScriptsSource();
    };

    using ExtraNatives = NativesCollection<EXTRAS>;

#ifdef V8_USE_EXTERNAL_STARTUP_DATA
    // Used for reading the natives at runtime. Implementation in natives-empty.cc
    void SetNativesFromFile(StartupData* natives_blob);
    void ReadNatives();
    void DisposeNatives();
#endif

    class NativesExternalStringResource final
        : public v8::String::ExternalOneByteStringResource {
    public:
        NativesExternalStringResource(NativeType type, int index);

        const char* data() const override { return data_; }
        size_t length() const override { return length_; }

        v8::String::ExternalOneByteStringResource* EncodeForSerialization() const
        {
            DCHECK(type_ == EXTRAS);
            intptr_t val = (index_ << 1) | 1;
            val = val << kSystemPointerSizeLog2; // Pointer align.
            return reinterpret_cast<v8::String::ExternalOneByteStringResource*>(val);
        }

        // Decode from serialization.
        static NativesExternalStringResource* DecodeForDeserialization(
            const v8::String::ExternalOneByteStringResource* encoded)
        {
            intptr_t val = reinterpret_cast<intptr_t>(encoded) >> kSystemPointerSizeLog2;
            DCHECK(val & 1);
            int index = static_cast<int>(val >> 1);
            return new NativesExternalStringResource(EXTRAS, index);
        }

    private:
        const char* data_;
        size_t length_;
        NativeType type_;
        int index_;
    };

} // namespace internal
} // namespace v8

#endif // V8_SNAPSHOT_NATIVES_H_
